By Dr. Mercola
The importance of sleep cannot be overstated, and the fact that the Nobel Prize in Physiology or Medicine just went to three biologists1,2,3,4,5 — Jeffrey Hall, Michael Rosbash and Michael Young — for their discovery of master genes that control your body's circadian rhythms only strengthen this position.
Your body contains not just one biological clock, but a vast array of clocks that regulate everything from metabolism to psychological functioning. Over the long term, skimping on sleep — which is a surefire way to dysregulate your circadian clock — can contribute to a whole host of chronic health problems. It also raises your risk of accidents and occupational errors.
The Many Health Hazards of Insufficient Sleep
As noted by NPR,6 "Studies show if you mess with the body's sleep-wake cycle, your blood pressure goes up, hunger hormones get thrown off and blood sugar regulation goes south. Over time … this may set the stage for metabolic diseases such as diabetes."
Indeed, research shows reducing your sleep by a single hour per night increases the expression of genes associated with inflammation, immune excitability, diabetes, cancer risk and stress.7 Even the Centers for Disease Control and Prevention (CDC) has stated that lack of sleep is a public health epidemic, noting that insufficient sleep has been linked to a wide variety of health problems. This includes but is not limited to:
Reduced ability to learn or remember
Reduced productivity at work and poor grades in school
Reduced ability to perform tasks
Reduced athletic performance
Reduced creativity at work or in other activities
Slowed reaction time
Increased risk of neurological problems, ranging from depression to dementia and Alzheimer's disease
Increased risk of Type 2 diabetes, obesity, cancer, high blood pressure, osteoporosis and cardiovascular disease
Decreased immune function
Reduced regulation of emotions and emotional perception
Increased susceptibility to stomach ulcers
Contributes to premature aging by interfering with growth hormone production, normally released by your pituitary gland during deep sleep
Shift workers, insomniacs and travelers crossing time zones are far from the only ones affected by circadian disruptions. Just staying up late watching television or working on your computer (or surfing the net on your iPad or cellphone) will have a similarly detrimental effect.
The blue light emitted by screen technology very effectively inhibits melatonin production, making it difficult to fall asleep and stay asleep through the night. Electromagnetic fields (EMFs) from these kinds of technologies also have significant effects. I'll address both of these issues below.
Desynchronization of Body Clocks Is an Underlying Factor of Chronic Disease
While the master clock in your brain synchronizes your bodily functions to match the 24-hour light and dark cycle, each and every organ, indeed each cell, has its own biological clock. That's a lot of clocks! As mentioned in this NPR interview with Fred Turek, a circadian scientist at Northwestern University, this was a rather stunning discovery. Even half of your genes have been shown to be under circadian control, turning on and off in cyclical waves.
Turek suggests a good way of thinking about all of these body clocks is to envision each organ clock as an instrument in an orchestra. All of them, while having slightly different rhythms, are synchronized to the master clock — the conductor in this analogy — in your brain. When these clocks become desynchronized, health problems ensue. Take the example of a shift worker: His brain is telling him that, since it's nighttime, he should not be eating.
However, since he'll be asleep during regular feeding hours, he ends up eating in the middle of his shift, which turns out to be in the middle of the night. Now, his pancreas is taken by surprise. Listening to the master clock in the brain, it's not expecting food and is therefore not quite up for the task. However, when food arrives, it has to release insulin anyway, despite the competing cues.
Essentially, the presence of food demands the pancreas override cues from the master clock in the brain, but in so doing, the organ gets desynchronized from the master clock. Research shows each and every organ basically has its own rhythm of activity and rest — times of the day or night when function is at its peak, and times when function is at its lowest.
This is why people who eat their main meal earlier in the day lose more weight than those who eat their main meal late at night — 25 percent more weight, in fact, which is a rather significant difference.8
Your metabolism is not functioning optimally late at night, so calories consumed are not metabolized as efficiently as during the earlier part of the day, when your body activity and metabolism are at peak. A number of other studies have also shown that working the night shift raises your risk of obesity.9 One analysis of 28 studies involving more than 270,000 people found night shift workers were 23 percent more likely to be obese than day shift workers.10
Acute Disease Risks and Effects of Medication Also Rise and Fall With Cyclic Regularity
Since each organ has its own rhythm, your risk for an acute health problem related to that organ, and the effect of medication, will rise and fall with cyclic regularity. For example, your blood pressure is tied to a rhythm that causes the most rapid increase in pressure early in the morning, so blood pressure medication is most effective when taken before you even get out of bed.
You're also 49 percent more likely to suffer a stroke between the hours of 6 a.m. and noon than you are at any other time of the day, thanks to the confluence of certain circadian rhythms. Remarkably, the toxicity of any given drug can also fluctuate from 20 to 80 percent depending on the time of day you take it.11
As noted by Dr. Clifford Saper, professor of neuroscience at Harvard Medical School,12 "The most common misconception is that people think that they do not have to follow the rules of biology, and can just eat, drink, sleep, play or work whenever they want."
The Genes That Control Your Circadian Rhythm
To get to the bottom of how the biological clock actually works, Hall and Rosbash built on fruit flyexperiments initially done by Seymour Benzer and Ronald Konopka in the 1970s.13 Rosbash summarizes this and other important research in the featured video. It was in fact Benzer and Konopka who first discovered that mutations in a single gene, named simply the period gene, could alter the fruit fly's circadian rhythm.
Using technologies that were unavailable in the '70s, including recombinant DNA technology, Hall and Rosbash were eventually able to answer the question of "What exactly is the period gene doing?" As explained in The Guardian:14
"Using fruit flies, the team identified a 'period' gene, which encodes a protein within the cell during the night which then degrades during the day, in an endless feedback cycle … Scientists discovered the same gene exists in mammals and that it is expressed in a tiny brain area called the suprachiasmatic nucleus, or SCN. On one side, it is linked to the retina in the eye, and on the other side it connects to the brain's pineal gland, which pumps out the sleep hormone melatonin."
Young, the third scientist to share the prestigious Nobel Prize for Physiology or Medicine, was responsible for identifying another gene with which the period gene interacts, thereby forming a coherent biological clock that regulates sleep, hormone levels, metabolism, behavior and more. To summarize, the protein encoded by the period gene — which is expressed in your SCN — is called PER. Again, PER increases at night and slowly degrades and diminishes during the day.
The second gene, named the "timeless gene," encodes a protein called TIM. This protein works in tandem with PER to regulate the period gene in your SCN (and hence the level of PER protein), thereby creating an oscillating rhythm that rises and falls every 24 hours. The short video below explains how your SCN, the master control clock in your brain, is influenced by the rhythm of light and dark.
Light Pollution Impedes Quality Sleep
Unfortunately, the challenge of getting quality sleep increases each year as new technological devices are produced that keep you entertained when you'd be better off sleeping. When you are forced to go without electricity, such as when camping or if the power goes out, you sleep deeper and arise more rested. It's important to realize that light sources at night interrupt your circadian clock and melatonin levels, both responsible for how deeply you sleep and well rested you feel the next day.
Aside from electronic screens, LEDs and fluorescent lights are particularly troublesome because of the isolated blue light peaks that are not balanced by red and near infrared.15 Importantly, LEDs may promote age-related macular degeneration, which is the leading cause of blindness. To learn more about this, please see my interview with Dr. Alexander Wunsch, a world class expert on photobiology, embedded here for your convenience.
Incandescent lights, on the other hand, emit red and near infrared wavelengths and very little in the blue wavelengths, making them a far healthier type of lighting. However, one must also be wary of light intensity, so if you have too bright of an incandescent light, that can cause problems. The lower the light the better after sunset, candlelight being the ideal.
Remember it is important to expose yourself to bright sunlight in the morning and/or around solar noon to "set" your master clock, and to avoid blue light exposure after sunset for the same reason. You also need to be mindful of avoiding light penetration while sleeping. Research16 reveals even dim light exposure during sleep can affect your cognition the next day, so ideally, use blackout shades or an eye mask.
How to Compensate If You Must Work the Night Shift
Working the night shift is a significant sacrifice that even the best health care plan cannot make up for. If you have any choice at all, I recommend doing everything in your power to avoid it. If you absolutely must work the night shift, you can somewhat ameliorate the adverse effects (although never fully offset them) by:
1. Getting 15 to 30 minutes of blue light exposure upon waking (which in your case would be in the evening or at night). The best blue light is from the sun, as it is balanced with other wavelengths. However, since sunlight will not be available at this hour, you can use a conventional clear incandescent bulb to simulate sunrise.
2. Follow this with a cool white (blue enriched) LED bulb, to mimic the sun's ascent toward high noon. You need both of these lights, not one or the other, as the LED will give you the blue and the incandescent the balancing red and near infrared spectrum. This will help you to establish your new circadian rhythm.
Once you feel the photonic energy boost, you can stop the LED use, since an overdose causes more harm than good. Bluish (LED) light generates excessive amounts of free radicals if not adequately balanced by red and near infrared light.
3. Always wearing blue-blocking glasses during your night shift.
Remember, your best choice is to stop working the night shift and get full sunlight exposure in the daytime. It's virtually impossible to imitate the full spectrum and brightness of natural sunlight, even with a high-quality UV lamp, cool white LED bulbs and bright incandescent lights.
It's better than nothing, but by working nights, you are depriving yourself of a crucial component for health, namely natural sunlight. The sun's rays not only are the catalyst that allows your skin to produce vitamin D, but sunlight also plays a role in mitochondrial health and is important for healthy vision.
The Importance of Avoiding Nighttime EMF
Another factor that can have a significant impact on your sleep quality and health is EMF exposure. This is true regardless of the time of your exposure, but it's particularly problematic at night. There's evidence showing EMF exposure reduces melatonin production,17 making it really important to eliminate EMFs in your bedroom. One of the easiest ways to do this is to pull the circuit breaker to your bedroom before going to bed.
Also remember that melatonin not only regulates your sleep-waking cycle; it's also a powerful antioxidant, and low levels have been repeatedly linked to an increased risk of cancer. As noted in one 2014 review:18
"The melatonin secretion by the pineal gland is generally regarded as particularly sensitive to electric, magnetic, and electromagnetic field influences. The effects of these fields on pineal activity have been analyzed in epidemiological studies and experimental investigations carried out using different in vivo and in vitro models.
The epidemiological studies provided interesting and very important data on the influence of electromagnetic fields on melatonin and its metabolite — 6-sulfatoxymelatonin — in humans. Many of these investigations concerned the effects of an extremely low frequency magnetic field (ELF-MF), which is generated by outdoor high- and medium-voltage electricity power lines, indoor electrical power supply, and electrical appliances …
Davis et al. suggested that domestic exposure to a 60 Hz magnetic field decreased pineal activity in women, primarily those using medications. The level of 6-sulfatoxymelatonin excretion was lower in infants kept in incubators and rose when they were moved to a place free from electrical devices.
The analysis performed by Juutilainen and Kumlin suggests that exposure to a magnetic field with a frequency of 50 Hz may enhance the effects of night-time light exposure on melatonin production …"
How to Improve Your Sleep Quality
Increasing the number of hours you sleep to eight each night and improving your quality of sleep may help to significantly reduce your risks associated with sleep deprivation. Below are several suggestions that may help.19,20 For a more comprehensive list of strategies, see my previous article, "Want a Good Night's Sleep? Then Never Do These Things Before Bed."
Turn your bedroom into an oasis for sleep
Your bed is a place to sleep and rest comfortably. Only two other activities will not significantly impede a restful sleep: reading and intimate relations with your significant other. Anything else, such as work, computers, cells phones or watching television will reduce the quality of your sleep.
Reduce any noisy interruptions from pets or outdoor activities. You might consider removing your pet from the bedroom or using a white noise machine to reduce interruptions from outdoor noises.
But the single MOST IMPORTANT step you can take to improve your sleep is to turn off the electricity in your bedroom before you go to sleep. Get a battery powered clock if you need to but there is little to no doubt in my mind that this is crucial for sleeping well.
Establish a soothing pre-bedtime routine
Humans are creatures of habit. When you establish a soothing bedtime routine you go through each evening before bed, you're more likely to fall asleep easily. Activities such as a warm bath, reading a good book or relaxation exercises may help you fall asleep easier.
If you have trouble falling to sleep one night, it's better to leave the bedroom and read quietly than to try even harder to fall asleep. I would strongly recommend using blue-blocking glasses if you do this, to prevent your reading light from further depressing your melatonin production.
Keep a consistent schedule
When you go to bed and wake up at the same times, your body becomes accustomed to the routine. This helps regulate your circadian clock so you fall asleep and stay asleep all night. Keep this routine even on the weekends.
Get plenty of bright sunlight exposure in the morning and at noon
Exposure to bright light first thing in the morning stops production of the sleep-inducing hormone melatonin and signals to your body that it's time to wake up. Outdoor sunlight is best, so you might even want to take a quick walk outside. Not only will this increase in physical activity help you sleep later, but taking your walk outdoors — either first thing in the morning or around noon when the sun high — gives you more exposure to bright sunlight.
Light intensity is measured in lux units, and on any given day, the outdoor lux units will be around 100,000 at noon. Indoors, the typical average is somewhere between 100 to 2,000 lux units, about two orders of magnitude less. I take a one-hour walk every day in the bright sunlight on the beach, so along with boosting my vitamin D, I also anchor my circadian rhythm at the same time and I rarely if ever have trouble sleeping.
At sundown, dim your lights (and/or use amber or, even better, red-colored glasses)
In the evening (around 8 p.m.) you'll want to dim your lights and turn off electronic devices. Normally, your brain starts secreting melatonin between 9 p.m. and 10 p.m., and these devices emit light that may stifle that process. After sundown, shift to a low-wattage incandescent bulb with yellow, orange or red light if you need illumination.
A salt lamp illuminated by a 5-watt bulb is an ideal solution that will not interfere with your melatonin production. If using a computer or smartphone, install blue light-blocking software like Iris — an improved version of f.lux.
The easiest solution, however, is to use amber-colored glasses that block blue light. I found a Uvex model (S1933X) or, even better, the red version for the same price. Both are available on Amazon, cost less than $10 and work like a charm to eliminate virtually all blue light.
This way you don't have to worry about installing programs on all your devices or buying special light bulbs for evening use. Once you have your glasses on, it doesn't matter what light sources you have on in your house.
Your body thrives on exercise and movement. It reduces your risk of cardiovascular disease and metabolic disorders. Exercise will help you get to sleep more easily and sleep more soundly. However, your body also releases cortisol during exercise, which may reduce your melatonin secretion. Exercise at least three hours before bed, and earlier if you can.
Keep your room cool
The optimal temperature for sleeping is between 60 and 68 F. If your room is cooler or warmer, you may have a more restless night's sleep.21 During sleep your body's core temperature drops to the lowest level during a 24-hour period. The cooler your room is, the more conducive it may be to your body's natural drop in temperature.
Evaluate your mattress and pillow
You'll experience more restful sleep when your mattress and pillows are comfortable and supportive. You'll want to consider replacing your mattress after nine or 10 years, the average life expectancy of a good quality mattress. Ideally, you will want to sleep on your bed with your pillow standing vertically to support your cervical spine. You can see the recent article I published on this.
Downshift your mental gymnastics before bed
Put all your work away at least one, and preferably two, hours before bed. You need a chance to unwind before falling asleep without being anxious about the next day's plans or deadlines.